I am (or my wife is) pregnant so I have to get rid of our guinea pig(s). FALSE
Guinea pigs are no threat to the health of a developing baby.
This concern stems from the possibility of contracting Toxoplasmosis from infected cat feces, which is also a low risk occurance.
In short, you need not get rid of any pets you have.
This link from the Humane Society of the US has great information regarding Toxoplasmosis and how to reduce chances of possible infection from cats during pregnancy.
http://www.hsus.org/pets/pet_care/pr...plasmosis.html
Info courtesy of LobsterOverlord.